Heat pipe

ABSTRACT

A heat pipe includes a casing and a supporting member. The casing is made of titanium and has a first end and a second end at two opposite sides thereof. The first end defines a receiving space therein. The supporting member is made of a material selected from one of copper, aluminum, stainless steel, low-carbon steel, iron, nickel, tungsten, tantalum, molybdenum, rhenium and columbium. The supporting member is received in the receiving space of the first end of the casing. The first end of the casing and the supporting member are integrally cramped and sealed.

BACKGROUND

1. Technical Field

The present invention relates generally to a heat pipe, and particularlyto a heat pipe which has a pipe body made of titanium and a sealed endmade of at least a ductile metal.

2. Description of Related Art

Heat pipes have excellent heat transfer performance due to their lowthermal resistance, and are therefore an effective means for transfer ordissipation of heat from heat sources. Currently, heat pipes are widelyused for removing heat from heat-generating components such as centralprocessing units (CPUs) of computers. A heat pipe is usually a vacuumcasing containing therein a working medium, which is employed to carry,under phase transitions between liquid state and vapor state, thermalenergy from one section of the heat pipe (typically referring to as the“evaporator section”) to another section thereof (typically referring toas the “condenser section”).

Presently, titanium is preferred for use as a material to make heatpipes than copper due to its light weight, high strength and highresistance to corrosion. However, titanium has a greater rigidity thancopper, whereby cracks would be incurred on a sealed end of the titaniumheat pipe when an open end of the heat pipe is cramped to form thesealed end. Thus, a vacuum degree of the heat pipe would be graduallydecreased due to the cracks of the heat pipe.

Therefore, it is desirable to provide a heat pipe which can overcome theabove described shortcoming.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present embodiments can be better understood withreference to the following drawings. The components in the drawings arenot necessarily drawn to scale, the emphasis instead being placed uponclearly illustrating the principles of the present embodiments.Moreover, in the drawings, like reference numerals designatecorresponding parts throughout the several views.

FIG. 1 is an isometric view of a heat pipe in accordance with anexemplary embodiment of the present invention.

FIG. 2 is a longitudinally cross-sectional view of the heat pipe of FIG.1, taken along line II-II thereof.

FIG. 3 is an enlarged view of a circle portion III of FIG. 2.

DETAILED DESCRIPTION

Referring to FIGS. 1-2, a heat pipe 1 includes a sealed casing 10containing a working fluid (not shown) therein, a wick structure 12disposed on an inner surface of the casing 10 and a supporting member 16received in the casing 10.

The casing 10 is made of titanium. The casing 10 has a first end 13, asecond end 14 opposite to the first end 13 of the casing 10, and amiddle main portion 15 between the second end 14 and the first end 13.The first end 13 defines a receiving space 136 therein. The first end 13includes a shrinkage portion 131 connecting with the middle main portion15 of the casing 10, a connecting portion 132 connecting with theshrinkage portion 131 and a sealing portion 133 connecting with theconnecting portion 132. The shrinkage portion 131 has a taperedconfiguration and an outer diameter of the shrinkage portion 131gradually decreases along an axial direction from the second end 14 ofthe casing 10 toward the first end 13 of the casing 10. The connectingportion 132 has a tube-shaped configuration and extends longitudinallyoutwardly from the shrinkage portion 131. The sealing portion 133 isflat and has a top wall 134 and a bottom wall 135 spaced from eachother.

The supporting member 16 is made of a material with low rigidity andgood ductility such as copper, aluminum, stainless steel, low-carbonsteel, iron, nickel, tungsten, tantalum, molybdenum, rhenium andcolumbium. In the preferred embodiment, the supporting member 16 is madeof copper.

The supporting member 16 is received in the receiving space 136 of thefirst end 13 of the casing 10. An outer circumferential surface of thesupporting member 16 is tightly attached to an inner circumferentialsurface of the first end 13 of the casing 10. The supporting member 16includes a positioning portion 161 corresponding to the shrinkageportion 131 of the casing 10, a tube-shaped connecting portion 162corresponding to the connecting portion 132 of the casing 10 and a flatsealing portion 163 corresponding to the sealing portion 133 of thecasing 10. The positioning portion 161 and the sealing portion 163 aredisposed at two opposite ends of the supporting member 16. Theconnecting portion 162 is disposed between the positioning portion 161and the sealing portion 163 of the supporting member 16.

The positioning portion 161 has a tapered configuration and an outerdiameter of the positioning portion 161 gradually decreases along anaxial direction from the second end 14 of the casing 10 toward the firstend 13 of the casing 10. An outer circumferential surface of thepositioning portion 161 of the supporting member 16 is tightly attachedto an inner circumferential surface of the shrinkage portion 131 of thecasing 10. The connecting portion 162 of the supporting member 16 has anouter diameter the same as an inner diameter of the connecting portion132 of the casing 10. An outer circumferential surface of the connectingportion 162 of the supporting member 16 is tightly attached to an innercircumferential surface of the connecting portion 132 of the casing 10.An outer circumferential surface of the sealing portion 163 of thesupporting member 16 is tightly attached to an inner circumferentialsurface of the sealing portion 133 of the casing 10.

The sealing portion 133 of the casing 10 is cramped to form the top wall134 and the bottom wall 135, whereby the sealing portion 163 of thesupporting member 16 is cramped to form a top wall 164 and a bottom wall165 intimately connected to the top wall 164. A free end 137 of thesealing portion 133 of the casing 10 and a free end 167 of the sealingportion 163 of the supporting member 16 are connected and sealedtogether by welding.

In manufacturing the heat pipe 1, the casing 10 is provided, with thesecond end 14 of the heat pipe 1 being integrally sealed and the firstend 13 being open. Then, the supporting member 16 is provided andinserted into the receiving space 136 of the first end 13 of the casing10. The first end 13 is shrunk to form the shrinkage portion 131 and theconnecting portion 132. The positioning portion 161 and the connectingportion 162 of the supporting member 16 are accordingly formed. Theshrinkage portion 131 of the casing 10 prevents the supporting member 16from moving longitudinally outwardly. The sealing portion 133 of thecasing 10 is cramped to cause the sealing portion 133 of the casing 10and the sealing portion 163 of the supporting member 16 to be flattened,whereby the top wall 163 and the bottom wall 164 of the sealing portion163 of the supporting member 16 are intimately connected together.Finally, the free end 137 of the sealing portion 133 of the casing 10and the free end 167 of the sealing portion 163 of the supporting member16 are welded, so that the heat pipe 1 is hermetically sealed. When thesealing portion 133 of the casing 10 is cramped, the sealing portion 133is prevented from cracking since the supporting member 16, which is madeof a material having a low rigidity and good ductility in comparisonwith titanium supports the sealing portion 133 of the casing 10. Thus,the heat pipe 1 can have a better hermetically sealing effectiveness, incomparison with that attainable by a heat pipe purely made of titanium.It is well known by those skilled in the art that before the cramping ofthe sealing portions 133, 163 of the casing 10 and the supporting member16, the working fluid is injected into the casing 10 and the air in thecasing 10 is vacuumed via a hole in the sealing portion 163.

It is believed that the present embodiments and their advantages will beunderstood from the foregoing description, and it will be apparent thatvarious changes may be made thereto without departing from the spiritand scope of the invention or sacrificing all of its materialadvantages, the examples hereinbefore described merely being preferredor exemplary embodiments of the invention.

1. A heat pipe comprising: a casing made of titanium and having a firstend and a second end at two opposite sides thereof, the first enddefining a receiving space therein; and a supporting member being madeof a material selected from one of copper, aluminum, stainless steel,low-carbon steel, iron, nickel, tungsten, tantalum, molybdenum, rheniumand columbium, the supporting member being received in the receivingspace of the first end of the casing, the first end of the casing andthe supporting member being integrally cramped and sealed.
 2. The heatpipe as claimed in claim 1, wherein an inner peripheral surface of thefirst end is tightly attached to an outer peripheral surface of thesupporting member.
 3. The heat pipe as claimed in claim 1, wherein thefirst end comprises a shrinkage portion and a sealing portion at twoopposite ends thereof, the shrinkage portion has a tapered configurationand an outer diameter of the shrinkage portion gradually decreases alongan axial direction from the second end of the casing toward the firstend of the casing.
 4. The heat pipe as claimed in claim 3, wherein thesupporting member comprises a positioning member corresponding to theshrinkage portion of the casing and a sealing portion corresponding tothe sealing portion of the first end of the casing, the sealing portionof the supporting member is flat and has a top wall and a bottom wallintimately connected to the top wall.
 5. The heat pipe as claimed inclaim 4, wherein a free end of the sealing portion of the first end ofthe casing and a free end of the sealing portion of the supportingmember are connected and sealed together by welding.
 6. The heat pipe asclaimed in claim 1 further comprising a wick structure disposed in theheat pipe and working fluid contained in the heat pipe.
 7. A heat pipe,comprising: a casing made of titanium and having a first end and asecond end at two opposite sides thereof, the first end defining areceiving space therein; and a supporting member made of a materialdifferent from titanium, the supporting member being received in thereceiving space of the first end of the casing, the first end of thecasing and the supporting member being integrally cramped and sealed. 8.The heat pipe as claimed in claim 7, wherein the supporting member ismade of a material selected from the group consisting of copper,aluminum, stainless steel, low-carbon steel, iron, nickel, tungsten,tantalum, molybdenum, rhenium and columbium.
 9. The heat pipe as claimedin claim 8, wherein an outer peripheral surface of the supporting memberis tightly attached to an inner peripheral surface of the first end ofthe casing.
 10. The heat pipe as claimed in claim 9, wherein the firstend of the casing comprises a shrinkage portion and a sealing portion attwo opposite ends thereof, the shrinkage portion has a taperedconfiguration and an outer diameter of the shrinkage portion graduallydecreases along an axial direction from the second end of the casingtoward the first end of the casing.
 11. The heat pipe as claimed inclaim 10, wherein a free end of the sealing portion of the casing and afree end of the sealing portion of the supporting member are connectedand sealed together by welding.
 12. The heat pipe as claimed in claim 7further comprising a wick structure disposed in the heat pipe andworking fluid contained in the heat pipe.
 13. The heat pipe as claimedin claim 12, wherein the supporting member is made of copper.